A redox reaction always involves
A. a change in oxidation number
B. a change in phase
c. the transfer of protons
D. the formation of ions
Answer:a
Explanation:
If 10 staples have a mass of 1.33 g, what will be the mass of 225 staples?
A.
29.9 g
B.
169 g
C.
1.69 kg
D.
2.99 kg
Answer:
A) 29.9g
Explanation:
first find the weight of 1 staple.
then multiply with 225
Answer: A
Explanation: 1.33/10 = .133
.133* 225 = 29.925 which is about 29.9 grams
What is the valence of oxygen
Answer:
-2
Explanation:
eACH ELEMENT HAS AN SPECIFIC VALENCE, FOR EXAMPLE, CARBON (+2),+4 IN THE CASE OF OXYGEN IS -2
NEED HELP DESPERATELY!!!
What assumption can be made about the density of two cylinders with similar masses and very different volumes?
A
mass-32
volume 23 mL
B
mass-31
volume 30 ml
PLS help ASAP
I rly don't want to fail 6th grade
Answer:
The density of tube A is greater then the density of tube B having more mass inside of the smaller area.
Explanation:
Answer:
A is denser.
Explanation:
1. An acetic acid solution that is 60.0% HC2H302 (by mass) contains
60.0 g acetic acid and 100.0 g water
60.0 g acetic acid and 40.0 g water
60 moles of acetic acid
60.0 g acetic acid and 60.0 g water
Answer:
A solution of acetic acid that is 60.0% HC₂H₃O₂ (by mass) indicates that it contains 60.0 g of acetic acid and 100.0 g of water.
Explanation:
A percentage is a way of expressing an amount as a fraction of 100. The mass percentage corresponds to physical units of the solutions and they allow to establish more precisely the concentration of the solutions and express them in terms of percentages.
Mass percentage indicates the amount in grams of solute per 100 grams of solution.
So a solution of acetic acid that is 60.0% HC₂H₃O₂ (by mass) indicates that it contains 60.0 g of acetic acid and 100.0 g of water.
What is the pH of a solution that has a H+ concentration equal to 1.7 x 10-5 M?
5.20
0.22
10.20
4.77
Considering the definition of pH, the pH is the last option, 4.77.
In firts place, you need to know that pH is a numerical scale used to specify the acidity or alkalinity of a solution. The pH is related to hydrogen ions, since it indicates the amount of these ions present in a solution or substance.
Mathematically, pH is defined as the opposite of the base 10 logarithm or the negative logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions:
pH= -log [H⁺]
The pH scale varies from 0 to 14, being acidic solutions with a pH lower than 7 and basic those with a pH greater than 7, while the pH value 7 corresponds to neutral substances.
In this case, being [H+]=1.7×10⁻⁵ M, you can replace this value in the definition of pH:
pH= -log (1.7×10⁻⁵ M)
Solving:
pH=4.77
Then, the pH is 4.77.
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How many moles of O2 are needed to produce 50.0 moles of CO2?
2 C8H18 + 25 O2 --> 16 CO2 + 18 H20
a) 78.1 moles
Answer:
4 moles
Explanation:
Please see the step-by-step solution in the picture attached below.
Hope this answer can help you. Have a nice day!
It requires 2,500 joules to raise a certain amount of water (c = 4.186J/g°C) from 20.0°C to 65.0°C.
What is the mass of the water that is being heated?
a 80 g
b 138
c 40 g
d 158 g
Answer:
The answer above is correct - the right option is A.
Explanation:
Hope this helped confirm!
When two or more substances are changed into different substances
O
chemical reaction
chemical equations
stoichiomety
O
freezing
Answer: A chemical reaction is a process in which some substances change into different substances. Substances that start a chemical reaction are called reactants. Substances that are produced in the reaction are called products. Reactants and products can be elements or compounds.
What are the names of the reactants in the reading
passage? 10 points
P + O2 →P4O10
Answer:
The reactants are Phosphorus and Oxygen .
Explanation:
In the equation above, P represents Phosphorus and O represents Oxygen or Oxygen gas.
Which type of material becomes molten rock at subduction zones?
Answer:
Heavy plates
Explanation:
Took the test, sorry.
An electron-pair acceptor is:
Lewis acid.
Lewis base
Arrhenius acid
Brønsted-Lowry base
Answer:
number3
Explanation:
Which liquid has the strongest base?
Liquid A-pH of 4.0
Liquid B-pH of 7.0
Liquid C- pH of 8.0
Liquid D-pH of 11.0
Answer:
water
Acidity and basicity are usually determined in a solvent. The strongest acid in the solvent is always the conjugate acid of the solvent and the strongest base is the conjugate base of the solvent. So, in water, the strongest acid is H3O+ and the strongest base is OH- (conjugate base of water).
Based on your graph in the Periodic Trends Lab, what is the relationship between atomic radius and ionization energy ?
PLEASE HELPPP!!!
The vapor pressure of a substance is 792 kPa at 0.0 degrees Celsius. What
is the vapor pressure of water at this temperature expressed in atmospheres?
a.1.04 atm
b. 3.26 atm
c. 7.82 atm
d. 5.62 atm
Answer:
I'm pretty sure it's A but I am not 100 present
hope this helps ❤️
pH revolves around a ‘point of focus’ we call what ______________?
Answer:
Equivalence point
Explanation:
In most cases, this point has a pH value of 7, but can vary
Answer:
The answer to this question is the equivalence point which has a pH of 7. It is neither acidic or basic. Therefore, it is an equivalence point.
A balloon starts off with 0.00035 moles of air and has a volume of 0.0081
L. It is inflated to a size of 1.5 L, how many moles of air are in the balloon
now?
Answer:
0.0648 mols
Explanation:
A cylinder with a constant volume of 2.80 L has a pressure of 32.0 psi at a temperature of 25 deg Celcius. If the cylinder is warmed to a temperature of 75 deg. Celcius, what will be the pressure inside the cylinder?
Ideal gas law is valid only for ideal gas not for vanderwaal gas. Charles' gas law is used here. Therefore the new pressure of the given gas is 5.63 atm.
What is ideal gas equation?
Ideal gas equation is the mathematical expression that relates pressure volume and temperature. Vanderwaal gas acts as ideal gas at low pressure and high temperature. There is no forces of attraction between the particles of an ideal gas.
Mathematically the relation between Pressure, volume and temperature can be given as
PV=nRT
where,
P = pressure of gas
V= volume of gas
n =number of moles of gas
T =temperature of gas
R = Gas constant = 0.0821 L.atm/K.mol
At constant volume
P₁/T₁ = P₂/T₂
32.0 psi ÷298 K =P2÷348 K
P2 = 7.55÷1.34 = 5.63 atm
Therefore the new pressure of the given gas is 5.63 atm.
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Where is the least amount of energy transferred in a food web?
Group of answer choices
From primary consumer to secondary consumer
From secondary consumer to primary consumer
From secondary consumer to producer
From producer to secondary consumer
Answer:
From primary consumer to secondary consumer; that is the answer!
Answer: "From primary consumer to secondary consumer"
Explanation:
I took the test (good luck)
Consider the following generic chemical reaction:
2A+3B→3C How many moles of B are required to completely react with: 8 mol of A, 9 mol of A, 3 mol of A, and 10 mol of A?
Answer:
The number of moles of B that will completely react with;
8 moles of A is 12 moles of B
9 moles of A is 13.5 moles of B
3 moles of A is 4.5 moles of B
10 moles of A is 15 moles of B
Explanation:
From the reaction, we have the mole ratio of the reactants is 2 moles of A combines with 3 moles of B to form 3 moles of C
Therefore, one mole of A which is 2 moles/2 will combine with 3/2 moles of B
Hence 8 moles of A will combine with 8×3/2 or 12 moles of B
9 moles of A will combine with 9×3/2 or 13.5 moles of B
3 moles of A will combine with 3×3/2 or 4.5 moles of B
10 moles of A will combine with 10×3/2 or 15 moles of B
The number of moles of B reacted in each case is obtained by stoichiometry.
The representation of a chemical process on paper is known as a chemical reaction equation. It must consist of a reactant side and a product side. The reactants combine to yield the product.
Given the reaction; 2A + 3B → 3C, we can see that the mole ratio of the reactants is 2 : 3. Hence;
2 moles of A reacts with 3 moles of B
8 moles of A reacts with 8 moles × 3 moles/2 moles
= 12 moles B
2 moles of A reacts with 3 moles of B
9 mol of A reacts with 9 mol × 3 moles/2 moles
= 13.5 moles of B
2 moles of A reacts with 3 moles of B
3 mol of A reacts with 3 mol × 3 moles/2 moles
= 4.5 moles of B
2 moles of A reacts with 3 moles of B
10 mol of A reacts with 10 mol × 3 moles/2 moles
= 15 moles of B
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The summer is caused by __________.
Which phrase best completes the sentence?
Earth's far distance from the sun
direct sunlight striking Earth
Earth's closeness to the sun
indirect sunlight striking Earth
Answer:
direct sunlight striking earth
Explanation:
The seasons are caused by Earth's axis of rotation. The poles are farther away from the direct beam of sunlight, so they are normally much colder than the equator.
When a part of the globe is in direct sunlight, it gets hotter, logically, and we call that season summer.
Hello, can someone help me? Please
Which velocity changed the most?
Answer:
A
Explanation:
Since acceleration is the change of velocity and f=ma, the change in velocity is dependent on force and mass. Since the force on all of the objects is the same, the one with the least mass will accelerate the most. Object A is the least massive at a mass of 0.5kg, meaning that its velocity will change the most. Hope this helps!
periods on the periodic table are
Answer:
Periods on the periodic table of elements
Explanation:
In the periodic table of elements, there are seven horizontal rows of elements called periods. The vertical columns of elements are called groups, or families. (See also The Periodic Table: Metals, Nonmetals, and Metalloids.) In each period (horizontal row), the atomic numbers increase from left to right.
how are cone bearing trees and static electricity connected
Answer: Static electricity will help in seed dispersal in cone bearing seeds.
Explanation:
Static electricity is the stationary electric charge produced by the friction. The static electricity can be produced by the turbulence or air currents in the storm clouds. This is responsible for the cause of lightening phenomena.
The cone bearing seeds exhibit cones that are hard and woody in nature. The static electricity due to the effect of lightening generate electrical shock which breaks open the cone and disperse the seeds. Thus the static electricity is important for seed dispersal in cone bearing trees.
The movement of material from a more crowded area to a less crowded area is called
A. Diffusion
B. Respiration
C. Osmosis
D. Photosynthesis
The movement of material from a more crowded area to a less crowded area is called diffusion, which achieves equilibrium when the concentration of molecules is equal in both areas.
The movement of material from a more crowded area to a less crowded area is known as diffusion. This natural process involves molecules moving from an area of higher concentration to an area of lower concentration. The process continues until the concentration of molecules is equal in both areas, achieving a state called equilibrium.
Diffusion is also described as the movement of solutes "down the concentration gradient." Osmosis is a specific type of diffusion pertaining to the movement of water across a semi-permeable membrane due to a concentration difference. However, since the question does not specify water or a semi-permeable membrane, the best answer would be option A, which is Diffusion. Respiration and photosynthesis, on the other hand, are biological processes involved in energy conversion and do not describe the movement of materials from a more crowded to a less crowded area.
A professor insists that a research scientist in her laboratory repeat an
experiment, despite the fact that the experiment took several weeks to
complete. Which best explains the professor's reasoning?
Answer:
This is to make sure that the experiment is precise as outside disturbance could cause false outcome
1. What is an ecosystem!
A :All the living things on Earth
B:All the nonliving things on Earth
C:All the plants and animals that interact with each other on Earth
D:All the living and nonliving things in a place or region that interact
with each other
Answer:
The answer is D.
Explanation:
Answer:
D. All the living and nonliving things in a place or region that interact
with each other
Which material gives the soil its high fertility? bedrock sand silt humus
Answer:
Humus
Explanation:
D
Humus gives the soil its high fertility. Therefore, the correct option is option D among all the given options.
What is soil?The living, porous media that has grown in the top layer of the Earth's crust is known as soil. As a source of nutrients and water, a filter for harmful wastes, a site for their breakdown, and a participant for the cycle of carbon and various other elements throughout the planet's ecosystem, soil is one of the main substrates of life on Earth.
It has changed as a result of weathering processes influenced by geographical, geologic, biological, and climatic factors. A practical understanding of soils as well as their management has also developed out of need since the development of crops and forests in the eighth millennium BCE. Humus gives the soil its high fertility.
Therefore, the correct option is option D.
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I need help on this question!!
(The actual question and options are in the picture below)
Answer:
A
Explanation:
This picture represents a stationary front. Stationary fronts often form clouds and, in particularly low pressure, have rain or snow. Therefore, the first answer choice is correct. Hope this helps!
Predict the molar volume of hydrochloric acid required to produce 55 mol of hydrogen gas at STP. A) 0.045 mol/L B) 3.7 M C) 8.9 mol/L D) 15 L
Answer:
A) 0.045 mol/L